https://nanyte.com/photoresists/su-8-3050 · last updated 2026-07-26
- Manufacturer
- Kayaku MicroChem / MicroChem Corp.
- Tone
- negative
- Chemistry
- Epoxy (SU-8 type)
- Thickness
- 44.3–101.3 µm
- Developer
- SU-8 Developer (MicroChem's proprietary solvent-based developer); ethyl lactate and diacetone alcohol are also stated to work
- Applications
- MEMS structural · High aspect ratio · Electroplating / molding
- Substrate
- Resist
- Exposed
Spin coating
Data points
| Series | rpm | µm | Published dose |
|---|---|---|---|
| SU-8 3050 | 1000 | 101 | — |
| 2000 | 67 | 150–250 mJ/cm² · 40–80 µm rows (2) | |
| 3000 | 50 | 150–250 mJ/cm² · 40–80 µm rows (2) | |
| 4000 | 44 | 150–250 mJ/cm² · 40–50 µm rows (3) |
Values are the manufacturer’s starting points, not a guarantee — characterize on your own tool. Series digitized from a published figure are approximate (±10 %).
Published dose is the datasheet’s own thickness bracket, quoted as printed — the full table and its citation are in the exposure section. A thickness the table does not cover shows nothing, and a thickness within 10 % of a bracket edge shows every bracket it could fall in.
read from Figure 1, 'Spin speed vs. Thickness for SU-8 3000 resists (21°C US & EU)', p.1 of the Kayaku Microchem/MicroChem 'SU-8 3000 Permanent Epoxy Negative Photoresist' datasheet (BYU cleanroom mirror; no printed revision code) -- the same datasheet and figure used for SU-8 3025. The chart plots five grades (3050/filled square, 3035/filled triangle, 3025/filled diamond, 3010/filled circle, 3005/open square), each with 4 markers at 1000/2000/3000/4000 rpm. SU-8 3050 is the filled+stroked square marker and the topmost (largest thickness) of the five stacked markers at every rpm column, consistent with it being the highest-viscosity grade (12,000 cSt, Table 1) and its top-of-legend position.
- Recommended Program (family-wide, not grade-specific): dispense 1 ml resist per inch (25 mm) of substrate diameter
- spin at 500 rpm for 5-10 s at 100 rpm/s acceleration (spread step)
- then spin at 3000 rpm for 30 s at 300 rpm/s acceleration as a generic starting point -- the actual final rpm/time for a target SU-8 3050 thickness should be read from Figure 1 ('Spin speed vs. Thickness for SU-8 3000 resists', 21°C US & EU, p.1, the curve plotted above) or Figure 2 (23°C Japan & Asia, p.2, which is not plotted here).
- No numeric table exists for SU-8 3050 alone -- Table 1 (p.2) only ranks the five grades by viscosity (3050: 75.5% solids, 12,000 cSt, 1.153 g/ml density).
- No edge-bead-removal step is described anywhere in this SU-8 3000 datasheet, and no resist rehydration hold is mentioned either.
- Adhesion
- HMDS not required — Adhesion promoters are stated as 'typically not required' for substrates cleaned per the recommended piranha (H2SO4+H2O2) wet etch or RIE/O2-barrel-ash prep.
Soft bake
- Soft bake
- 95 °C · hotplate
- Notes
- 95°C is fixed across all thickness brackets; only bake TIME varies by film thickness per Table 2: 4-10 µm -> 2-3 min; 8-15 µm -> 5-10 min; 20-50 µm -> 10-15 min; 30-80 µm -> 10-30 min; 40-100 µm -> 15-45 min. The brackets are indexed by film thickness rather than by grade, and they overlap: this grade's own spin curve runs from 44.3 µm at 4000 rpm (which sits in the 20-50, 30-80 and 40-100 µm rows at once) to 101.3 µm at 1000 rpm (just past the top of the table), so bake to the row matching the thickness actually coated.
SOURCE: Table 2 'Soft Bake Times', p.2 of SU-8 3000 Permanent Epoxy…
Table 2 'Soft Bake Times', p.2 of SU-8 3000 Permanent Epoxy Negative Photoresist datasheet, Kayaku MicroChem/MicroChem Corp.
Exposure dose
SU-8 3050's dose is published against film thickness, not as a single number. Read the row for the film you coat and run a dose array around it.
- As published
- SU-8 3050's thinnest coat, 44.3 µm, lands in three of the table's overlapping brackets at once — 20–50, 30–80 and 40–100 µm — and all three read 150–250 mJ/cm².
- Post-exposure bake
- 95 °C · 3–5 min
| Film thickness | Dose |
|---|---|
| 4–10 µm | 100–200 mJ/cm² |
| 8–15 µm | 125–200 mJ/cm² |
| 20–50 µm | 150–250 mJ/cm² |
| 30–80 µm | 150–250 mJ/cm² |
| 40–100 µm | 150–250 mJ/cm² |
SOURCE: Table 3 'Exposure Dose', p.2 of the SU-8 3000 Permanent Epoxy…
Table 3 'Exposure Dose', p.2 of the SU-8 3000 Permanent Epoxy Negative Photoresist datasheet, Kayaku MicroChem/MicroChem Corp. Brackets are indexed by film thickness and overlap exactly as printed. Not attributed to a specific wavelength — the document recommends i-line but states conventional UV (350-400 nm) is most common.
Development
- Developer
- SU-8 Developer (MicroChem's proprietary solvent-based developer); ethyl lactate and diacetone alcohol are also stated to work
- Rinse
- Spray/wash with fresh SU-8 developer for ~10 s, then a second spray/wash with isopropyl alcohol (IPA) for ~10 s, then air/nitrogen dry with filtered pressurized gas.
- Developer family
- Solvent
Not published for this resist: Dilution, Time, Method — characterize on-tool.
SOURCE: Develop and Rinse-and-Dry sections, p.3 of SU-8 3000 Permanent…
Develop and Rinse-and-Dry sections, p.3 of SU-8 3000 Permanent Epoxy Negative Photoresist datasheet, Kayaku MicroChem/MicroChem Corp.
Hard bake, etch & strip
- Hard bake
- 150–200 °C
- Descum
- Not published — characterize on-tool
- Etch resistance
- Listed under Features as 'Excellent dry etch resistance' (p.1, no numeric selectivity given).
- Stripper
- MicroChem's Remover PG, 50-80°C bath, 30-90 min immersion -- swells and lifts off minimally-crosslinked SU-8 3000; achieves a clean, thorough lift-off of fully-crosslinked SU-8 3000 only if a 30-100 nm OmniCoat sacrificial layer was applied first.
- Storage
- Store upright, in tightly closed containers, in a cool, dry environment away from direct sunlight, at 40-70°F (4-21°C).
SOURCE: Hard Bake (cure) section, p.3 of SU-8 3000 Permanent Epoxy…
Hard Bake (cure) section, p.3 of SU-8 3000 Permanent Epoxy Negative Photoresist datasheet, Kayaku MicroChem/MicroChem Corp.
Where it's used
Practical notes from the datasheet
SU-8 3050 is the highest-viscosity member (12,000 cSt, 75.5% solids, 1.153 g/ml) of Kayaku MicroChem's five-grade SU-8 3000 permanent epoxy series (3005/3010/3025/3035/3050), an 'improved formulation' of SU-8 2000 offering better adhesion and lower coating stress for thick (family-wide 4-120 µm single-coat), high-aspect-ratio (>5:1), permanent MEMS structures that are imaged, cured, and left on the device rather than lifted off. Within the 3000 series it is the thickest-coating grade at any given spin speed -- its own curve runs from 101.3 µm (1000 rpm) down to 44.3 µm (4000 rpm), stacked above 3035/3025/3010/3005 at every rpm column, consistent with its top rank by viscosity. It is generally preferred over the matching SU-8 2050 grade (SU-8 2000 series) when a thick, high-aspect-ratio process suffers adhesion loss or stress cracking, since the 3000 line was reformulated specifically to reduce both. Softbake time, PEB time, and develop time are all published as THICKNESS-BINNED ranges common to the whole 3000 series (not per-grade single values), and the brackets overlap, so each of those steps quotes the full bracket table and no single time is stated for the grade; exposure dose is likewise indexed to film thickness, and the datasheet does not attribute Table 3's doses to a single wavelength. As with the rest of the SU-8 family, fully cross-linked SU-8 3050 is notoriously difficult to strip: MicroChem's Remover PG only lifts minimally-crosslinked resist (or fully-crosslinked resist sitting over a sacrificial OmniCoat layer); a hard-baked film with no OmniCoat underneath requires piranha etch, plasma ashing, RIE, laser ablation, or pyrolysis to remove.
Grades in this family
Other grades in the SU-8 3000 series line differ mainly in coating thickness:
| Grade | Thickness |
|---|---|
| SU-8 3050 (this page) | 44.3–101.3 µm |
| SU-8 3025 | — |
Sources & disclaimer
- Kayaku MicroChem / MicroChem Corp. — SU-8 3050 datasheet · accessed 2026-07-22
Manufacturer datasheet values are starting points; optimal parameters depend on your substrate, equipment and environment. Product names and trademarks belong to their respective owners. NANYTE is not affiliated with the manufacturers listed. Last updated 2026-07-26.